VYCOR® PRO Data Sheet

High performance self-adhered flashing with non-asphaltic butyl-modified adhesive

The Better the Seal, the Better the Performance

The primary purpose of a flashing tape is to prevent the migration of water and air through window and door openings. Product performance depends on the adhesive bond between the flashing and the substrate. This is especially true for irregularly surfaced materials such as OSB. The better the adhesive seals itself into the peaks and valleys of the substrate, the better the barrier against water and air migration. 

Moisture Control is the First Step to Mold Control

Water from both exterior and interior sources is among the worst enemies of building structures. When moisture enters and remains within the wall system, it creates a favorable environment for the development of rot, mold and mildew. Repairing these types of problems can be very difficult and extremely costly.

Air Control is the First Step to Better Energy Performance

The key to optimizing energy performance is preventing the movement of air both into and out of the building envelope. Air leaks around window and door openings make it difficult to keep a comfortable indoor environment, forcing the HVAC system to work harder, while driving up energy costs.

A properly integrated flashing tape that adheres and seals aggressively to the substrate will create the most effective barrier against water and air migration while acting as a drainage plane to shed water down the exterior of the building envelope.

What Makes VYCOR® PRO Flashing Different?

VYCOR® PRO flashing, with its unique film and non-asphaltic, butyl-modified adhesive technology, provides premium protection against water infiltration in all critical non-roof detail areas, that traditional building papers, felts, housewraps and other flashing products cannot match.

In addition, VYCOR® PRO’s wide application and service temperature windows make it appropriate for use in any environment.

Product Description

VYCOR® Pro flashing is composed of a durable, tear and puncture resistant engineered polypropylene backing film, paired with an aggressive, non-asphaltic, proprietary butyl-modified adhesive. VYCOR® PRO flashing comes in 75 ft rolls and is available in:

  • 4 in. (102 mm)
  • 6 in. (150 mm)
  • 9 in. (225 mm)
  • 12 in. (305 mm)


VYCOR® PRO flashing is a unique solution appropriate for working around a number of detail areas, including, but not limited to:

  • Window and door openings (headers, sills, jambs, thresholds, nailing flanges)
  • Deck-to-wall intersections
  • Corner boards
  • Wall-to-wall tie-ins
  • Foundation sill plates
  • Sheathing panel seams
  • Under stucco finishes
  • Masonry walls
  • Application to EPDM in vertical applications
  • Other non-roof detail areas

Features & Uses

  • Superior adhesive capabilities — Non-Asphaltic, proprietary butyl-modified adhesive seals and adheres to the substrate creating a best-in-class barrier against air and water intrusion.
  • Seals around fasteners — The specially formulated adhesive seals around fasteners, preventing water penetration.
  • Forms water-tight laps — VYCOR® PRO’s superior adhesion properties ensure strong overlaps. 
  • Highly Conformable — Thin and pliable membrane is easily worked into tight details.
  • Wide application window — Primerless adhesion to wood sheathing from 25°F (4° C)
  • Wide Service Temperature Window — Suitable for in-service conditions up to 176° F (80° C)
  • Long exposure time — 120 days of exposure provides protection over long, unpredictable construction cycles
  • Flexible Application — VYCOR® PRO’s wide performance window makes it appropriate for use in all regions
  • Easy to work with — This high performance barrier membrane is easy to apply with 6 and 12 inch (150 mm and 305 mm) measurement markings.
  • Superior Weather Protection Solution — Use in combination with VYCOR® ENV-S™ or VYCOR ENV® fully-adhered weather barriers to provide superior protection from wind driven rain.


  • VYCOR® Pro flashing contains no asphalt, and is fully compatible with rigid and flexible PVC window nailing flanges.
  • Compatible with common weather resistive barriers and many types of sealants. Refer to Technical Letter 1, Chemical Compatibility with Other Building Materials and Sealants for more information.

Application Instructions

Apply in fair weather to clean and dry surface at air temperatures of 25°F (4°C) or higher. Apply directly to substrate. Compatible substrates include wood, plywood, oriented strand board, exterior gypsum, metal, concrete and masonry. Install VYCOR® PRO flashing with weather-resistive barriers to form water-shedding laps. Cut membrane to length. Peel back release liner. Align membrane and press into place. Mechanically fasten membrane at vertical terminations as necessary. Press or roll into place with hand roller to achieve best adhesion. Primer is generally not required for most substrates (including plywood, OSB, dimensional lumber, PVC window flanges, steel, and aluminum) provided they are clean and dry. On concrete, masonry and glass fiber surfaced gypsum sheathing apply Perm-A-Barrier® WB Primer at a coverage rate of 250–350 ft2/gal (6–8 m2/L). Regardless of substrate, if adhesion is found to be marginal, prime substrate material with Perm-A-Barrier® WB Primer at the same coverage rate.

Precautions & Limitations

SLIPPERY — DO NOT install on the roof. Do not leave permanently exposed to sunlight. Maximum recommended exposure is 120 days. May be applied to EPDM in vertical applications. Some caulks containing high levels of hydrocarbon solvents may be incompatible with the adhesive in VYCOR® PRO flashing. Check with the caulk manufacturer or your local GCP Applied Technologies technical sales representative and/or refer to Technical Letters published on the GCP Applied Technologies web site.


Meets AAMA 711-13 specification for self-adhered flashing Level 3 requirement for elevated temperature exposure.

Product Data

Property VYCOR® PRO    
Product Thickness 14 mil (0.61 mm)    
Carrier film Engineered Polypropylene    
Adhesive Non-Asphaltic, Proprietary butyl-modified adhesive
Release liner Paper Release      
Color White with Green Paint    
Recommended exposure limit 120 Days      
Roll width(s) 4 in. (102 mm) 6 in. (102 mm) 9 in. (102 mm) 12 in. (102 mm)
Roll length(s) 75 ft (22.9 m) 75 ft (22.9 m) 75 ft (22.9 m) 75 ft (22.9 m)
Rolls per carton 12 8 4 4
Shipping weight per carton 37 lbs (17 kg) 37 lbs (17 kg) 28 lbs (17 kg) 37 lbs (17 kg)
Cartons per pallet 60 60 84 60

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We hope the information here will be helpful. It is based on data and knowledge considered to be true and accurate, and is offered for consideration, investigation and verification by the user, but we do not warrant the results to be obtained. Please read all statements, recommendations, and suggestions in conjunction with our conditions of sale, which apply to all goods supplied by us. No statement, recommendation, or suggestion is intended for any use that would infringe any patent, copyright, or other third party right.

Vycor, Vycor enV, and Perm-A-Barrier are trademarks, which may be registered in the United States and/or other countries, of GCP Applied Technologies Inc. DensGlass Gold is a registered trademark of Georgia-Pacific Corporation. This trademark list has been compiled using available published information as of the publication date and may not accurately reflect current trademark ownership or status.

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GCP Applied Technologies Inc., 2325 Lakeview Parkway, Suite 400, Alpharetta, GA 30009, USA
GCP Canada, Inc., 294 Clements Road, West, Ajax, Ontario, Canada L1S 3C6
This document is only current as of the last updated date stated below and is valid only for use in the United States. It is important that you always refer to the currently available information at the URL below to provide the most current product information at the time of use. Additional literature such as Contractor Manuals, Technical Bulletins, Detail Drawings and detailing recommendations and other relevant documents are also available on www.gcpat.com. Information found on other websites must not be relied upon, as they may not be up-to-date or applicable to the conditions in your location and we do not accept any responsibility for their content. If there are any conflicts or if you need more information, please contact GCP Customer Service.

Last Updated: 2023-06-28